Yes, your fan is on a slow road to death. Begin the process of getting it repaired. Due to parts availability issues, and some other problems not related to my laptop, it took two service centres and 5 months to get mine fixed. During that time, the left fan also died.
If you want, you can even install the iStat Pro widget or smcFanControl and watch your fan die its slow, noisy death. 😉
That happened to me but on the other side near the MagSafe. It was just a peice of Debris in ti and went away after a trip to the Apple Tech(Its funny in the same way when you go to see a doctor for a pain and when you get there its gone) ;^)
My noisy fan would mysteriously disappear every time I made the trip into the local service centre. And that noise eventually went away, too - when the fan died.
Just because the noise has stopped doesn't mean the fan is now functioning properly. Install smcFanControl or the iStat Pro widget to check your fan speeds ( 0 RPM means your fan is already dead), or run the system diagnostics off disk 1 of your OS X install package. Ignore a previously noisy fan at your peril.